import math

x1, y1, x2, y2 = [float(i) for i in input().split()]

bottom = x2 - x1
height = y2 - y1

print(math.sqrt(bottom**2 + height**2)) import math math float(i) for i in input().split() for i in input().split() i input().split() ().split () input split for i in input().split() float(i) float i x1, y1, x2, y2 = [float(i) for i in input().split()] x1 [float(i) for i in input().split()] y1 x2 y2 bottom = x2 - x1 bottom x2 - x1 x2 x1 height = y2 - y1 height y2 - y1 y2 y1 print(math.sqrt(bottom**2 + height**2)) print math.sqrt(bottom**2 + height**2) math.sqrt math sqrt bottom**2 + height**2 bottom**2 bottom 2 height**2 height 2 bottom = x2 - x1 x2 - x1 bottom y1, x2, y2 = [float(i) for i in input().split()] [float(i) for i in input().split()] y1 y2 = [float(i) for i in input().split()] [float(i) for i in input().split()] y2 height = y2 - y1 y2 - y1 height x1, y1, x2, y2 = [float(i) for i in input().split()] [float(i) for i in input().split()] x1 x2, y2 = [float(i) for i in input().split()] [float(i) for i in input().split()] x2
import math

x1, y1, x2, y2 = [float(i) for i in input().split()]

bottom = x2 - x1
height = y2 - y1

print(math.sqrt(bottom**2 + height**2))